Electron discharge device



June 21, 1949. R, C,y SCHMIDT 2,473,547

ELEGTRON DISCHARGE DEVICE Filed Sept. 28, 1945 2 Sheets-Sheet 1 Y Z [5 I8 /a li 2 /G l n l 6/ i;` Z4 :l

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Patenteci June 21;, 1949 UNITED STATES PATENT OFFICE ELECTRON DISCHARGE DEVICE Robert C. Schmidt, Newton, Mass., assignor to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application September 28, 1945, Serial No. 619,017

4 Claims. 1

Mgpresent invention relates to electron-discharge devices, and more particularly to electrondischarge devices of the so-called magnetron type.

While not limited thereto, my present invention is especially suitable for generating low, continuous-wave power, at low voltages, in the microwave region of the electromagnetic spectrum.

Devices of the general character indicated have heretofore required external magnetic means, and have, therefore, been bulky, and costly to manufacture and assemble. Hence, it is among the objects of my present invention to provide a selfcontained magnetron which is compact, and whose components are so designed and arranged as to enable the simple and inexpensive assembling thereof.

'Ihese and other objects of my present invention, which will become more apparent as the detailed description thereof progresses, are attained, briey, in the following manner:

In the magnetron of my present invention, a centrally-disposed cathode member is surrounded by a coaxial, cylindrical anode member provided with a plurality of radially-disposed cavity resonators, the annular space intermediate said cath-l ode and anode members constituting an electron path. A pair of opposed, permanent magnets is arranged on opposite sides of said anode member, in coaxial alignment therewith, to establish a magnetic field in a direction transversely of saidA electron path. The elements described are supported upon a base member, and are enclosed by an envelope, made of magnetic material, which is hermetically sealed to said base member, at least a part of said envelope constituting at least a part of the return path of the magnetic eld established by said permanent magnets. Power is extracted from the device by means of a coaxial line, entering the same through said base member, and being coupled to said anode member.

Such a structure is relatively simple to manufacture and assemble; it is self-contained; and it is compact, thereby eliminating the disadvantages of prior art devices hereinbefore referred to.

In the accompanying specification I shall describe, and in the annexed drawings show, an illustrative embodiment Vof the electron-discharge device of my present invention. It is, however, to be clearly understood that I do not wish to be limited to the details herein shown and described for purposes of illustration only, inasmuch as changes therein may be made without the exercise of invention and within the true spirit and scope of the claims hereto appended.

In said drawings,

Fig. 1 is a longitudinal sectional view taken substantially through the center of an electrondischarge device made in accordance with the principles of my present invention; and

Fig. 2 is an enlarged scale transverse sectional view taken along line 2--2 of Fig. 1.

Referring now more in detail to the aforesaid illustrative embodiment of my present invention, with particular reference to the drawings illustrating the same, the numeral I designates an octal hase on which is mounted an inverted dishlike header l i Secured to the header i l is a dishlike adapter l2 from which rises a plurality, here shown as four, of supporting rods i3 made of non-magnetic material, preferably, Monel metal.

Secured to the rods I3, adjacent the top and near the bottom thereof, is a pair of magnet-supporting discs I4 and l5, made of magnetic material, and, respectively, provided at their peripheries with flanges i5 and il directed toward each other, and lugs I3 and i9 punched out of the same to present openings Z and 2i through which the rods i3 may pass, said lugs constituting the means for fastening said discs to said rods.

Depending from the disc I, and extending upwardly from the disc l5, is a pair of similar, but magnetically opposed permanent magnets 22 and 23, said magnets, preferably, being cylindrical and provided, respectively, with central bores 24 and 25. Secured against the facing, inner ends of the magnets 22 and 23 is a pair of centrally-bored pole pieces 26 and 2l, said pole pieces being additionally supported, respectively, by rings 28 and 29 which are fastened to the rods i3, and the inner ends of said pole pieces being separated to provide a concentrated magnetic field in the space therebetween.

An anode-supporting ring 30 is secured to the rods I3 intermediate the pole-supporting rings 28 and 29, said ring 30 having depending therefrom a cylindrical anode block 3i, made of highly conductive material, such as copper, and provided with a multiplicity, here shown as twentyfour, of inwardly-directed, radially-disposed anode arms 32, each pair of adjacent anode arms, together with that portion of said anode block lying therebetween, constituting a cavity resonator whose natural resonant frequency is, as is well known, a function of the geometry of the physical elements making up the same. The anodeV arms 32 project into the magnetic eld intermediate the pole pieces 26 and 2l.

In order to suppress spurious oscillations, I prefer that alternate and intermediate anode arms 32 be electrically connected, adjacent their inner ends, respectively, by conducting rings 33 and 34 at the upper edges thereof, and by conducting rings 35 and 36 at the lower edges thereof.

Centrally disposed in the space defined by the inner ends of the arms 32, and extending into the central bores of the pole pieces 26 and 2l, is a cathode sleeve 3l made, preferably, of nickel, and provided, in a region coextensive with the height of said anode arms, with a highly electron-emis- ,the header' sive coating 38, for example, of the well-known alkaline-earth metal oxide type. Said cathode sleeve 37 is supported, preferably, in a pair of mica insulating discs 35 and 45, in turn, secured, by retaining rings di and 42, in recesses i3 and 44 formed, respectively, in the pole pieces"25 and 21.

The coating 38 is raised to emission temper-ature by a heating nlament 45 disposed in the cathode sleeve 37, one end of said lament being electrically connected to said Sleeve, as at 45, and the other end thereof being connected, as at 4l, to a lead-in conductor 48, which has its outer end secured in,a base pin 49, and which enters the inner region .of the device through a glass seal 55 carried by an eyelet 5i secured in il. The heating ilament circuit is completed by a conductor 52, one end of Which Yis electrically connected, as at 53, to the lower end of the cathode sleeve 37, and the other end of which is connected to a lead-in conductor (not shown), similar to the lead-in conductor "48, and entering the device through like means,

and terminating, forexample, at a base pin 54.

'From their respective lead-in conductors, the filament d5 and conductor 52 are separately conveyed through the central bore 25 of the magnet 23 by means of insulating tubes 55 and 56.

In order to protect the pole pieces 25 and 2l from cathode sputtering, the cathode sleeve 3lis provided with shields 57 and 58.

' The entire inner assembly is enclosed by a ,cylindrical envelope or can 59, made of magnetic material and hermetically sealed, as at 60,

to the adapter l2, the flanges I6 and l of thell magnet-supporting discs I4 and l5 being secured to said envelope, as at 6l and 52, whereby said envelope serves as a low-reluctance return path for the magnetic flux emanating from the mag- :nets 22 and 23.

The interior of the device is conventionally evacuated through an exhaust tubulation 53.

-Low, continuous-wave power, at loW voltages, may be extracted from the device by electrically 64 made, preferably, of nickel, said tab being secured at 'the end of an inner conductor'BE of a coaxial transmission line, and said conductor passing out of the device through a glass seal Y55 carried by an eyelet G'l aflixed to the header Il.

The external end of said conductor' 65 terminates in a nickel tube 68 disposed in a re- "cessed insulating member 59 which is carried at the outer end of an outer, tubular conductor 10 of the above-mentioned coaxial transmission line,

vsaid outer conductor 19 passing through openings 'H and 'l2 with which the discsv I5 and 29 are,

respectively, provided, and terminating just above the lower end of the anode block 3| This completes the description of the aforesaid illustrative embodiment of my present invention.

It will be noted from all of the foregoing that linvention will readily occur to those skilled in` the art to which the same relates.

What is claimed is: 1.1An electron-discharge device comprising: a

l cathode member; an anode member; said cathode and anode mem-bers being spaced topresent' 4, an electron path therebetween; means within said device establishing a magnetic eld in a direction transversely of said electron path; a base member: means, rising from said base member, sup- .,pcrting said cathode and anode members and said field-establishing means; and an envelope, hermetically sealed to said base member, and cooperable therewith to enclose said cathode and anode members and said field-establishing means; apart oi said envelope constituting a part of the return path of said magnetic field.

2. An electron-discharge device comprising: a centrally-disposed cathode member; an anode member surrounding said cathode member, and including a plurality 'of radially-disposed cavity resonators; said cathode and anode members being spaced to present an electron path. therebetween; means Within said device establishing a magnetic eld in a direction transversely of said electron path; a base member; means, rising irom said base member, supporting said cathode and anode members and said eld-estabiisliing means; and an-envelope, hermetically sealed to said base member, and cooperable therewith to enclose said cathode and anode members and said field-establishing means; a part of said envelope constituting a part of the return path oi magnetic eld.

3. An electron-discharge device comprising: a centrally-disposed cathode member; an-vanode member surrounding said cathodefmemberl and including a plurality of radially-disposed cavity resonators; said cathode and anode members being spaced to present an electron path therebetween; a pair of spaced, permanent magnets,

v coaxially aligned with said cathode andlanode i connecting to one of the anode arms 32 a tab145 operabie therewith tovenclose said cathode and anode members and said permanent magnets; a part of said envelope constituting a part ofA the return path of said magnetic eld.

4. An Yelectron-discharge device comprising: a cathode member; ananode member; saidvcathode and anode members being spaced ytopresent electronpath therebetween; a pair of yopposed magnets establishing a magnetic field in a direction transversely of saidelectron path;

, a base member; a plurality of rods extending from said base member; members extendingfrom said rods to support said anode member and ,said magnets; said cathodelmember being supported, in turn, by said magnets; and a can,.made1 of v magnetic material and hermetically sealed to said base, for enclosing said cathode and anode menibcrs and said magnets; a part of said can4 constituting a part of the returnpath of said-magnetic field,

ROBERT C. SCHMIDT.

REFERENCES CITED The following referenlcesare of record in the file of this patent:

UNITED 4STATES PATENTS 

